bending wood with a carbon fibre layer
Hi there
I’m a minimalist light and furniture designer in Victoria BC and have been bending wood for about 10 years now. I have a chair design that I have been working on for a while that involves some complex bending and entirely relies on the flexibility and strength of the bent pieces. At the moment the design is too flexible for my liking so I have been looking into adding a layer of carbon fibre to the lamination. This will stiffen it up and also look really cool too, with a black stripe visible on the edges.
I’m looking at using an eco type epoxy for this but, as I use a long thin vacuum bag with external form, I’m worried about the epoxy ruining the (very expensive) bag. Normally I use Titebond 2 Extend for my glue ups as I like the clear line and the extended working time. I am assuming that this won’t work with the carbon fibre, hence the plan to use epoxy.
Does anyone have any experience doing this sort of work or have any thoughts on vacuum bagging with epoxy.
Thanks so much
Mike Randall
Kurva Design
kurvadesign.ca
Replies
You could try a 2-step glueup... step 1 a traditional bent lamination on your external form to sandwich your carbon fiber part between 2 lams using epoxy and step 2 the rest of your layers around it in the vac bag using the TB2X.
Thanks so much, I hadn't thought of that..... I'll look into that.
I always put a layer of thick plastic between my work and the vacuum bag whether using epoxy or glue. I save heavy shipping plastic for this exact purpose. Also epoxy can be spread very thin so squeeze out should be minimal. Recently came across this video. Looks similar to what you are trying to do. Hope it works out.
https://youtu.be/EAYgEUJkTuY
If you want to make something "beam-like" stiffer, you need to add the strongest material on the outside, not the center. Think I-beam. Carbon is commonly used with model airplane spars (particularly sailplanes which require a lot more bending strength than you might think. The highest stresses are always in the layers farthest from the center of the spar/beam/whatever. Adding carbon to the center really won't add any substantial strength. You probably still want to add wood on the outside layers for appearance, but keep the carbon as far from the center as possible. Obviously, making some test pieces will help.
If using carbon fiber or cloth, the typical best ratio of fiber:epoxy is 1:1. The strength comes from the material, not the epoxy.
Maybe this is already known, but I thought I would contribute just in case.
This forum post is now archived. Commenting has been disabled